The Specialized Center of Research-Arteriosclerosis (SCOR-A) includes clinical and experimental research programs on arteriosclerosis. The major clinical program is a study of children for prevalence, distribution and course of "risk factors" related to atherosclerosis. During the past year, approximately 500 children have been studied in Franklinton, Louisiana. Prepilot and pilot studies were conducted to develop methods, techniques, and train personnel for the screening of 5000 children in Bogalusa. Protocols are now written, and data collected on the Franklinton children are being analyzed. Computer and editing programs have also been developed from these initial surveys. Although not complete, it is now possible to state means and ranges for such variables as weight, height, skinfold thickness, blood pressure, and a lipid profile on children, ages 5 to 14 years. The lipid profile includes serum cholesterol, triglycerides, and quantitation of serum alpha-, pre-Beta-, and Beta-lipoproteins. As found earlier, children tend to have high alpha-lipoprotein and lower pre-Beta- lipoprotein concentrations than observed in adults. A limited amount of nuritional data has also been obtained. All of the above studies, protocols, and methodology, are continually being refined. The initial studies in Bogalusa started Sept. 10, and indicate approximately 95 percent participation. Experimental research involves primarily studies of subhuman primates in an effort to develop new models for the study of atherosclerosis. Phylogenetic studies are exploring inter- and intraspecies differences in response to cholesterol-fat feedings and effect on serum lipoprotein concentrations. Considerable differences of serum lipoproteins in New and Old World monkeys have been observed. The effect of protein intake on serum lipoproteins is also being explored, and the experimental research attempts to complement the clinical studies.